Breech seal for caseless ammunition firearm

ABSTRACT

A truncated cone insert, positioned in a chamber in the breech block, and having a central bore for receiving the bolt, the reduced end of the cone being adjacent to the ammunition charge, and arranged to be radially compressed by the gas pressure, when fired, to seal the breech.

United States Patent [191 Scibor et al.

[ 1 Apr. 24,1973

I BREECH SEAL FOR CASELESS 3,501,858 3/1970 Hensley et al. ..89/26 AMMUNITION FIREARM 3.474.560 10/1969 Ramsay 3,496,828 2/1970 Donner 1 Inventors! Alphonse sclbol', 6540 Longacre, 2,480,l00 8/1949 Weiss et a]. ..89/26 Detroit, Mich. 48228; Bruce C. Nei- 6304 Martin Detroit, Mich- Primary Examiner-Stephen C. Bentley 48210 Attorney-Edward M. Apple [22] Filed: Apr. 16, 1971 [57] ABSTRACT [21] App]. No.: 134,592

A truncated cone insert, positioned in a chamber In the breech block, and having a central bore for receiv- U-S. 1 ing the bolt the reduced end of the cone being ad- [51] Int. Cl. ..F4lC 11/00 jace t t the ammunition charge, and arranged to be [58] Field of Search ..89/26; IOZ/DIG. 1 di ll compressed by the gas pressure, when fired, to

, seal the breech. [56] References Cited 3 Claims, 8 Drawing Figures UNITED STATES PATENTS 3,166,864 1/1965 Scanlon ..89/26 D-fi-U BREECII SEAL FOR CASELESS AMMUNITION FIREARM This invention relates to firearms and particularly to firearms designed to use caseless ammunition.

An object of the invention is to seal the breech mechanism against the rearward loss of gas when the firearm is fired.

Another object of the invention is to provide a perfect seal around the bolt assembly.

Another object of the invention is to provide a forwardly directed truncated cone element, which is radially compressed by the propulsion gases to effect a perfect seal around the bolt assembly.

Another object of the invention is to insert a truncated cone element in a section ofthe firing chamber, and around the bolt assembly, which element is provided with comparatively thin walls, at its leading end, and arranged to be radially compressed to seal the breech by the back pressure of the propulsion gases upon firing.

Another object of the invention is to provide a sealing member in the firing chamber of a firearm, through which is extended the bolt and firing pin, said member having comparatively thin walls at its leading end, and is provided with a plurality of radial fingers, which reduce the swirling of the gases in the chamber.

The foregoing and other objects and advantages of the invention will become more apparent as the description proceeds, reference being made from time to time to the drawing, in which:

FIG. 1, is a side elevational view of a bolt action rifle equipped with the sealing device embodying the inventron.

FIG. 2, is an enlarged section taken on the line 2-2 of FIG. 1.

FIG. 3, is a section taken substantially on the line 3 3 of FIG. 2.

FIG. 4, is a fragmentary detail, in section, showing the means for sealing the firing pin.

FIG. 5, is an enlarged detail, illustrating one method of securing the truncated cone in the chamber.

FIG. 6, is a view similar to FIG. 5, but showing a I modified way of mounting the cone.

FIG. 7, is an enlarged detail, showing a tapered bore in the bolt for receiving a matched taper on the firing pin, for helping to seal the gas loss.

FIG. 8, is an enlarged detail, in section, illustrating the movement of gases, and development of pressures at the moment of firing.

Referring now more particularly to the drawing, it will be understood, that in the embodiment herein disclosed, the reference character 11, indicates in general, a rifle which is equipped to fire caseless ammunition, and which is provided with the sealing mechanism embodying the invention.

The rifle 11 has a conventional barrel 12, stock 13, breech assembly 14, bolt lever 15, trigger mechanism 16, and trigger guard 17. These elements are conventional and form no part of the invention, except as they are combined with the elements hereinafter described. The barrel 12 (FIG. 2) has an internal bore 18, which is rifled, as at 19, and has a counter-bore 20, in which is received a caseless charge of ammunition 21, which is a compacted mixture of black powder and plastic, or other explosive, which is formed around an insert 22, which is an extension of the bullet or projectile 23. The

explosive charge 21 is provided with a primer 24, which is fired by the tip 25 ofa firing pin 26, which is slideable in an axial bore 27 formed in the bolt 28, which is acuated by the bolt lever 15, to move the charge 21 into the firing chamber 20 as in conventional practice. The bolt 28 is slideable in an axial bore 29, formed in breech block 30, to which the barrel 12 is attached by threading, as at 31. A seal between the breech block 30 and the barrel 12 is provided by means of a suitable gasket 32.

The breech block 30 has a comparatively large bore 33, which forms a chamber for receiving certain of the expanding gases, resulting from the firing of the caseless charge 21.

Inserted in the chamber 33 and secured therein by any suitable means, such as pressed fitting, (as shown in FIGS. 2 and 4,) by welding, (as shown in FIG. 5,) or by threading, (as shown in FIG. 6,) is a sealing member 34. The member 34 has a comparatively heavy base 35, and forwardly tapering walls 36, which in effect form a truncated cone. The walls at the leading end of the cone are comparatively thin, so that the expanding gases in the chamber 33 exert tremendous pressure on the thin walls, causing them to be compressed tightly against the bolt 28, to seal the passage way 29 against leakage of the explosive gases.

In order to prevent the swirling of the gases around the truncated cone, we provide a plurality of radial webs 37 on the walls of the cone. The webs 37 trap the gases in pockets around the periphery of the cone, which enhances the effective pressures developed in the gases, upon the firing of the firearm.

In order to further seal the breech against the leakage of gases around the firing pin 26, and around the bolt 28, we provide peripheral grooves 38 on the firing pin 26, and peripheral grooves 39 on the bolt 28. A further means for sealing the space between the firing pin 26 and the bolt 28 is provided by forming a bore 40 in the leading end of the bolt 28, which bore is provided with a seat 41, which is arranged to be contacted by a valve head 42, which is formed on the leading end of the firing pin 26. The expanding gases, upon the firing of the weapon, cause the head 42 to be received in the seat 41, so that little, if any, gas may escape passed the valve 42. The peripheral grooves 38 trap any gases which may escape passed the valve seat 41. By the same token, the peripheral grooves 39 trap any gases which escape passed the walls 36 of the sealing cone.

In FIG. 7 we show another means of sealing around the bolt. In this embodiment, the base 35 of the truncated, conical insert 34 is provided with a tapered bore 43, which is arranged to receive a similar taper 44, formed on the outside wall of the bolt.

In FIG. 8, we illustrate the mechanism at the moment of firing the firearm. In this view, the firing pin 25, has already struck the primer, and has exploded the charge 21. The developed explosive gases have started the propulsion of the bullet 23 toward the end of the rifle barrell. (As shown by the arrows pointing to the right). The back pressure of the gases have already seated the head 42 on the valve seat 41. The gases also enter the chamber 33 and exert pressure on the comparatively thin walls of the conical member 34, to compress the walls against the bolt 28, to seal the area around the bolt.

it is believed that the operation of the device is obvious from the foregoing description.

Having described our invention, what we claim and desire to secure by Letters Patent is:

1. In a firearm adapted to fire caseless ammunition, including a chamber for receiving said ammunition, a breech block having a passageway therein, for receiving a bolt for moving the ammunition from a storage magazine to said chamber, and a firing pin slideable in a passageway in said bolt, the combination of means at the leading ends of said passageways to seal said passageways against gas pressures developed in said chamber upon firing said ammunition, said sealing means having a truncated cone member positioned at the rear of said chamber, said cone having an axial passageway for receiving said bolt and having comparatively thin walls at the leading end arranged to squeeze said bolt to seal the space around said bolt upon the firing of said ammunition.

2. The structure of claim 1, in which said cone has a comparatively thick base portion which is secured to the walls of said chamber.

3. The structure of claim 1, in which the walls of said cone have a plurality of radial web members arranged to prevent the swirling of gases in said chamber around said cone. 

1. In a firearm adapted to fire caseless ammunition, including a chamber for receiving said ammunition, a breech block having a passageway therein, for receiving a bolt for moving the ammunition from a storage magazine to said chamber, and a firing pin slideable in a passageway in said bolt, the combination of means at the leading ends of said passageways to seal said passageways against gas pressures developed in said chamber upon firing said ammunition, said sealing means havinG a truncated cone member positioned at the rear of said chamber, said cone having an axial passageway for receiving said bolt and having comparatively thin walls at the leading end arranged to squeeze said bolt to seal the space around said bolt upon the firing of said ammunition.
 2. The structure of claim 1, in which said cone has a comparatively thick base portion which is secured to the walls of said chamber.
 3. The structure of claim 1, in which the walls of said cone have a plurality of radial web members arranged to prevent the swirling of gases in said chamber around said cone. 